The petroleum industry is increasingly turning to heavy crudes, resids, coals and tar sands, i.e., lower grade hydrocarbon, as sources for feedstocks. The upgrading or refining of these feedstocks is accomplished by treating the feedstocks with hydrogen in the presence of catalysts to effect conversion of at least a portion of the feeds to lower molecular weight hydrocarbons, or to effect the removal of unwanted components, or compounds, or their conversion to innocuous or less undesirable compounds.
Hydroconversion catalysts can be supported or unsupported. Supported catalysts are usually comprised of at least one Group VIB metal with one or more Group VIII metals as promoters on a refractory support, such as alumina. Unsupported mixed Group VIII and Group VIB metal catalysts and catalyst precursors used for hydroconversion processes are known in the art as disclosed in U.S. Pat. Nos. 2,238,851; 5,841,013; 6,156,695; 6,566,296 and 6,860,987, amongst others.
In the process of making and using hydrotreating catalysts, residues and wastes are generated in the form raw and intermediate materials as well as spent catalyst. As the environmental impact of waste disposal from industries has become increasingly scrutinized, there is a need to recycle or rework waste products to the extent possible. As base metals are quite expensive, it is also economical to recycle/reuse rework waste materials. There are a number of references in the prior art disclosing reworking/recycling catalyst products. U.S. Pat. No. 6,030,915 discloses a process for preparing a hydroprocessing catalyst employing ground (spent) regenerated hydroprocessing catalyst. US Patent Publication No. 20080060977 discloses a process to make an oxide catalyst with crushed fines of a fresh catalyst as one of the components.
There is still a need for improved catalysts having the appropriate morphology, structure, and optimum catalytic activity for high yield conversions of lower grade hydrocarbon feedstocks to higher value products. There is also a need for improved processes for making catalysts, particularly environmentally friendly processes that reuse or recycle waste products generated in the process of making catalysts.